Investigation of anomalous very fast decay regimes in homogeneous isotropic turbulence

Abstract : The emergence of anomalous fast decay regimes in homogeneous isotropic turbulence (HIT) decay is investigated via both theoretical analysis and eddy-damped quasi-normal Markovian simulations. The work provides new insight about a fundamental issue playing a role in HIT decay, namely the influence of non-standard shapes of the energy spectrum, in particular in the large energetic scale region. A detailed analysis of the kinetic energy spectrum E(k) and the non-linear energy transfer T(k) shows that anomalous decay regimes are associated with the relaxation of initial energy spectra which exhibit a bump at energetic scales. This feature induces an increase in the energy cascade rate, toward solutions with a smooth shape at the spectrum peak. Present results match observations reported in wind-tunnel experiments dealing with turbulence decay in the wake of grids and bluff bodies, including scaling laws for the dissipation parameter C-E. They also indicate that the ratio between the initial eddy turnover time and the advection time determines of how fast anomalous regimes relax toward classical turbulence free-decay. This parameter should be used for consistent data comparison and it opens perspectives for the control of multiscale effects in industrial applications.
Type de document :
Article dans une revue
Journal of Turbulence, Taylor & Francis, 2018, 19 (5), pp.390 - 413. 〈10.1080/14685248.2018.1450506〉
Liste complète des métadonnées

https://hal.archives-ouvertes.fr/hal-01816010
Contributeur : Elena Rosu <>
Soumis le : jeudi 14 juin 2018 - 16:26:32
Dernière modification le : vendredi 15 juin 2018 - 01:17:05

Identifiants

Collections

Citation

Marcello Meldi, Pierre Sagaut. Investigation of anomalous very fast decay regimes in homogeneous isotropic turbulence. Journal of Turbulence, Taylor & Francis, 2018, 19 (5), pp.390 - 413. 〈10.1080/14685248.2018.1450506〉. 〈hal-01816010〉

Partager

Métriques

Consultations de la notice

14